Enormous quantities of goods, including manufactured goods, produce and materials, are daily shipped around the world by land, sea and air in containers of various types. Standard shipping containers as used on seagoing ships, for example, are a familiar sight at sea and on land. The loading of cargo items into such containers and their subsequent unloading, is a major activity involving much expenditure of labour and money. An important problem facing all those involved in shipping of goods is containing the cost of such loading and unloading.
Much of the cost of loading and unloading arises from the need to secure cargo items in their containers securely, to avoid damage in transit. Given the wide variety of goods that must be transported, this can be a skilled process consuming much time and effort.
It is also important in many cases that cargo items not move within their containers during transit. In sea transport, for example, any inadvertent shifting of cargo due to ship motions can have adverse effects on ship stability and hence safety.
Some cargoes comprising multiple discrete items that can be loaded in a container in layers also present a problem in that no number of complete layers closely matches the load carrying capacity of the container, yet partial layers can be difficult to secure against undesired movement.
Materials such as timber used to secure heavy loads in containers can present quarantine and disposal problems at their destinations.
An issue widely recognized in the sea transport industry, at least, is that there can be a mismatch between cargoes and container sizes on particular journey legs. For example, where cargo movements are such that “40-foot” containers arrive at a particular port in numbers greater than are required for cargoes leaving that port, there can be excessive numbers of “dead legs” for such containers, i.e. journey legs where the containers are carried empty. Enhancing the ability of such containers to be loaded with other cargo items could in such a case lead to substantial cost savings by reducing dead legs.
More generally, it is always desirable to enhance the flexibility of loading of containers. For example, making it easier to use a small container where a large one was previously required, or vice versa, allows better matching of cargoes and container availability.
The present invention addresses these problems and issues and is applicable to cargo containers carried on land, sea and air transport vehicles. In addition, it may find application in transport modes where cargo items are contained by the structure of the carrying vehicle, for example where cargo items are carried between decks in ships, or in rail or road vehicles.